1. Technical Field
This invention pertains to power clamps and more particularly to clamps driven by electric motors. Clamps are used to secure an object to aid assembly or to secure it during transport from one location to another.
2. Description of the Related Art
The robotics and automation industry heavily relies on power clamps for securing objects such as mechanical or electrical components so those components can be integrated into an assembly or moved from one assembly station to another. Clamps of various sizes, shapes, and configurations have been used to secure objects ranging in size from as small as electronic circuit boards to as large as entire automobile body panels. Clamps can be comprised of opposing members, but are more commonly mounted to a work surface and use one arm to pin the object against the work surface.
The majority of clamps currently used in the automation industry are pneumatically powered. This is primarily due to the significantly greater power obtainable from a pneumatically powered clamp compared to existing electrical clamps of similar size. Disadvantages of prior versions of electric clamps include being large, complex, delicate, or expensive.
The present invention uses an innovative design to produce an electric clamp with high clamping power in a small and relatively inexpensive package. In one embodiment, the clamp of the present invention comprises an electrically powered clamp having a housing, a motor attached to the housing, a ball screw driven by the motor via a belt, and a linkage driven at one end by the ball screw such that the linkage rotates an output shaft attached to the other end of the linkage. The motor and belt drive the ball screw between a fully extended position to rotate the output shaft to a clamped position, and a fully retracted position to rotate the output shaft to an unclamped position. A built-in controller monitors and controls the clamp. The clamp can also be controlled and monitored by a remote pendant. Indicator lights on the housing and remote pendant convey clamp status information. The clamp is programmable and can memorize the clamped and unclamped positions. The clamp uses velocity and position feedback to determine appropriate drive mode. Torque monitors and timers determine if the clamp becomes stuck.